1. Field of the Invention
The invention relates to a device for testing the efficiency of a vapor recovery system, such as that employed with a gasoline dispensing system.
2. Discussion of the Related Art
One form of pollution is gasoline vapors that escape during re-fueling of a vehicle. When gasoline is dispensed into a vehicle, such as an automobile, the gasoline displaces the gaseous vapors in the gasoline tank. This causes the gaseous vapors to vent to the atmosphere. In some instances, these vapors make their way upwardly through the fill tube. However, in most instances, the manufacturer provides a separate tube between the tank and the fill neck for venting the vapors. Because of the potential for pollution caused by re-fueling vehicles, governmental regulations have required many geographical locations to provide a gasoline dispensing system which collects the vapors as the gasoline is dispensed. Within the gasoline dispensing system is a gasoline vapor recovery system which utilizes a vacuum to recover the vapors at the fill neck of the vehicle. This is accomplished by a gasoline nozzle which has a concentric spout, the concentric spout providing a vapor passageway around the liquid dispensing passageway. Apertures near the distal end of the outer spout allow the gaseous vapors to be vacuumed into the vapor passageway and returned to the underground gasoline supply tank. In many locations, government regulations establish acceptable performance levels for the gasoline vapor recovery system. Various tests have been established to check the efficiency performance of an individual vapor recovery system. These tests determine the ratio of the volume of the gasoline vapors recovered to the volume of the gasoline liquid dispensed which is referred to as the V/L ratio. If this ratio is one, for instance, then it can be said that a cubic foot of gasoline vapor is returned for every cubic foot of gasoline dispensed. This ratio is a key indicator of the performance of the vapor recovery system. Government regulations set an acceptable range of V/L ratios based upon measurements made during certification testing. In some areas, government regulations also establish a separate test for determining whether there is a blockage of the vapor recovery system.
The present testing devices for determining the V/L ratio are very bulky and require a considerable amount of time and effort to connect to a vapor recovery system. These devices are also very invasive of the gasoline dispensing system and create a spectacle which arouses curiosity. The use of these devices invariably require the vapor return hose to be broken and a large flow meter installed in the vapor return path. A bucket to hold the dispensed gasoline is also required. The gasoline then has to be disposed of by pouring it into the underground storage tank.
There is a need for a testing device which is compact, for example, briefcase size, and which can quickly test for the V/L ratio with minimal effort. Further, there is a need for a test device which will require no hauling or dumping of gasoline which is dispensed during the test.